Java 如何使用 BufferedWriter 写入标准输出
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How to write to Standard Output using BufferedWriter
提问by amccormack
I am currently writing an application that produces several log files using BufferedWriter. While debugging, however, I want to write to System.out instead of a file. I figured I could change from:
我目前正在编写一个使用 BufferedWriter 生成多个日志文件的应用程序。但是，在调试时，我想写入 System.out 而不是文件。我想我可以改变：
log = new BufferedWriter(new FileWriter(tokenizerLog));
to:
到：
BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
log.write("Log output\n");
as opposed to:
与：
System.out.println("log output")
The new OutputStreamWriteroption has not been working though. How do I change just the Object inside the BufferedWriter constructor to redirect from a file to Standard out. Because I have several log files I will be writing to, using System.out everywhere and changing the output to a file isn't really an option.
但是，新OutputStreamWriter选项并没有奏效。如何仅更改 BufferedWriter 构造函数中的对象以从文件重定向到标准输出。因为我有几个要写入的日志文件，所以在任何地方都使用 System.out 并将输出更改为文件并不是一个真正的选择。
采纳答案by Hyman
Your approach does work, you are just forgetting to flush the output:
您的方法确实有效，您只是忘记刷新输出：
try {
BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
log.write("This will be printed on stdout!\n");
log.flush();
}
catch (Exception e) {
e.printStackTrace();
}
The both OutputStreamWriterand PrintWriterare Writerinstances so you can just do something like:
两个OutputStreamWriter和PrintWriter是Writer实例，因此你可以这样做：
BufferedWriter log;
Writer openForFile(String fileName) {
if (fileName != null)
return new PrintWriter(fileName);
else
return new OutputStreamWriter(System.out);
}
log = new BufferedWriter(openForFile(null)); //stdout
log = new BufferedWriter(openForFile("mylog.log")); // using a file
or whatever, it is just to give you the idea..
或者别的什么，这只是给你的想法..
回答by SBA
Since you mention that this is for logging, you might want to look at using a logger library like log4j. It'll let you change the log destination (either log file or console) by making changes in configuration files only.
由于您提到这是用于日志记录，因此您可能需要考虑使用 log4j 之类的记录器库。它可以让您通过仅更改配置文件来更改日志目标（日志文件或控制台）。
